import os
import sys
import shutil
from typing import List

from django.core.management.base import AppCommand
from django.core.management.color import color_style

from django_extensions.management.utils import _make_writeable, signalcommand


class Command(AppCommand):
    help = "Creates a Django management command directory structure for the given app "
    "name in the app's directory."

    requires_system_checks: List[str] = []
    # Can't import settings during this command, because they haven't
    # necessarily been created.
    can_import_settings = True

    def add_arguments(self, parser):
        super().add_arguments(parser)
        parser.add_argument(
            "--name",
            "-n",
            action="store",
            dest="command_name",
            default="sample",
            help="The name to use for the management command",
        )
        parser.add_argument(
            "--base",
            "-b",
            action="store",
            dest="base_command",
            default="Base",
            help="The base class used for implementation of "
            "this command. Should be one of Base, App, Label, or NoArgs",
        )
        parser.add_argument(
            "--dry-run",
            action="store_true",
            default=False,
            help="Do not actually create any files",
        )

    @signalcommand
    def handle_app_config(self, args, **options):
        app = args
        copy_template("command_template", app.path, **options)


def copy_template(template_name, copy_to, **options):
    """Copy the specified template directory to the copy_to location"""
    import django_extensions

    style = color_style()
    ERROR = getattr(style, "ERROR", lambda x: x)
    SUCCESS = getattr(style, "SUCCESS", lambda x: x)

    command_name, base_command = (
        options["command_name"],
        "%sCommand" % options["base_command"],
    )
    dry_run = options["dry_run"]
    verbosity = options["verbosity"]

    template_dir = os.path.join(django_extensions.__path__[0], "conf", template_name)

    # walk the template structure and copies it
    for d, subdirs, files in os.walk(template_dir):
        relative_dir = d[len(template_dir) + 1 :]
        if relative_dir and not os.path.exists(os.path.join(copy_to, relative_dir)):
            if not dry_run:
                os.mkdir(os.path.join(copy_to, relative_dir))
        for i, subdir in enumerate(subdirs):
            if subdir.startswith("."):
                del subdirs[i]
        for f in files:
            if f.endswith((".pyc", ".pyo")) or f.startswith(
                (".DS_Store", "__pycache__")
            ):
                continue
            path_old = os.path.join(d, f)
            path_new = os.path.join(
                copy_to, relative_dir, f.replace("sample", command_name)
            ).rstrip(".tmpl")
            if os.path.exists(path_new):
                path_new = os.path.join(copy_to, relative_dir, f).rstrip(".tmpl")
                if os.path.exists(path_new):
                    if verbosity > 1:
                        print(ERROR("%s already exists" % path_new))
                    continue
            if verbosity > 1:
                print(SUCCESS("%s" % path_new))
            with open(path_old, "r") as fp_orig:
                data = fp_orig.read()
                data = data.replace("{{ command_name }}", command_name)
                data = data.replace("{{ base_command }}", base_command)
                if not dry_run:
                    with open(path_new, "w") as fp_new:
                        fp_new.write(data)
            if not dry_run:
                try:
                    shutil.copymode(path_old, path_new)
                    _make_writeable(path_new)
                except OSError:
                    sys.stderr.write(
                        "Notice: Couldn't set permission bits on %s. You're probably using an uncommon filesystem setup. No problem.\n"  # noqa: E501
                        % path_new
                    )
